Conventional sewing machines capable of embroidery sewing have been used that is provided with a cloth pressing mechanism that drives a cloth pressing member for pressing a workpiece cloth upon embroidery sewing, a thread cutting device that cuts a needle thread-end connected with a sewing needle, and a wiper mechanism that wipes up the cut needle thread-end with a wiper member.
For example, a wiper device for a sewing machine disclosed in JP-Y-6-52782 (hereinafter referred to as patent document 1) has a wiper body rotatably supported by a sewing machine frame, a presser foot for pressing a workpiece cloth, a reciprocating unit operating conjunctively with the vertical movement of the presser foot, and a connection link that connects the upper end of the wiper body to the upper end of the reciprocating unit. The reciprocating unit includes a support bar loosely fitted to a penetration hole defined on the presser foot and having a locking body in the lower portion thereof larger than the penetration hole; and a spring body supported by the support bar so as to receive the support bar therethrough.
According to the above construction, upon completion of a sewing operation, when the reciprocating unit is elevated in conjunction with the elevation of the presser foot, the wiper body is moved toward the sewing needle via the connection link and wipes up the needle thread-end cut by the thread cutting unit of the sewing machine.
Furthermore, in a thread wiping device disclosed in JP-A-2003-103080 (hereinafter referred to as patent document 2), a thread cutting device that automatically cuts the needle thread and a bobbin thread is provided near the underside of a needle plate of a sewing machine bed. Also a thread wiping device that pulls up the needle thread connected to the sewing needle above the needle plate and pulling out the needle thread-end from the workpiece cloth after cutting the needle thread with a thread cutting device is provided in a sewing machine head above the sewing machine bed.
The thread wiping device includes a wiper having a hook on the distal end thereof so that the needle thread can be pulled out from the workpiece cloth, a wiper drive mechanism that drives the wiper, and a needle thread retaining equipment provided on the wiper and retaining needle thread-end.
According to the above construction, upon completion of a sewing operation, when the needle bar and the cloth presser are elevated, the wiper is activated by the wiper drive mechanism and pulls the needle thread-end cut by the thread cutting device by hooking the needle thread with the hook. Thereafter, the needle thread-end is retained by the needle thread retaining equipment.
The wiper device disclosed in the patent document 1, merely pulls out the needle thread-end cut by the thread cutting unit above the workpiece cloth by the wiper member and does not retain the wiped needle thread. Thus, the needle thread-end is prone to twist, consequently leading to failure or deformation of initial stitches of the subsequent sewing sequence, and other similar problems.
Also, the thread wiping device disclosed in patent document 2 wipes up the needle thread with the wiper and retains the needle thread-end with the needle thread retaining equipment. However, the wiper is driven by the wiper drive mechanism in synchronization with the thread cutting movement of a moving blade of the thread cutting device, leading to increased complexity, size and cost of the thread wiping device.